The present invention is divided from copending Patent Application No.
8225840 (serial No. 2107524) which has a disclosure similar to that of the present application and in which there is claimed a magnetic valve comprising a movable valve member, a valve seat sealingly engageable by said valve member, a movable armature member for actuating said valve member in directions toward and away from said valve seat, means for interconnecting said armature member with said valve member for limited tilting rotational movement relative to said valve member in order to impart said limited tilting rotational movement to said valve member, said limited tilting rotational movement tending to pry or peel said valve member from said valve seat, magnet means for moving said armature member toward said magnet means and away from said valve seat when said magnet means
2 is energized, means for maintaining a non magnetic gap between said magnet means and said armature member when said mag netic means is energized in order to control the magnetic flux flow between said magnetic 70 means and said armature member, the thick ness of said non-magnetic gap being non uniform so that said magnetic flux flow is correspondingly non-uniform in order to facili tate said limited tilting rotational movement of said armature member when said magnet means is energized.
Preferably, the armature member of such a magnetic air valve is provided with a non magnetic covering or coating, preferably of a predetermined thickness, to serve as the non magnetic gap, or an -artificial air gap", be tween the armature member and the eiectro magnet to control the magnetic flux flow therebetween when the electromagnet is ener gized. The preferred covering or coating in cludes an inner layer of relatively inexpensive, easy-to-apply non-magnetic material and an outer layer of a relatively hard, wear-resistant non-magnetic material. The inner layer is pre ferably composed of copper or a copper-con taining substance, and the outer layer is pre ferably composed of electroless nickel or a nickel-containing substance.
According to the present invention there is provided a method of forming a non-magnetic gap between a magnetic flux-producing apparatus and a magnetic armature engageable with said magnetic fluxproducing apparatus, comprising the steps of: covering said armature member with a first layer of a nonmagnetic material; polishing said armature to smooth the surface of said first layer; covering said first layer with a second layer of a relatively hard non-magnetic material; and polishing said armature to smooth the surface of said second layer; said first and second layers thereby forming said non-magnetic gap. Preferably the first layer comprises a copper- containing non-magnetic material and the sec- ond layer comprises a nickel-containing nonmagnetic material.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side cross-sectional view of an 115 exemplary embodiment of a magnetic valve made using the method of this invention.
Figure 2 is an end view of the magnetic valve of Fig. 11; Figure 3 is a partial side cross-sectional 120 view of the magnetic valve of Fig. 1 illustrat ing the operation thereof; and Figure 4 is an enlarged view of a corner portion of the armature member of the mag- netic valve of Fig. 1.
In Figs. 1-3, an exemplary magnetic valve 10 is illustrated. Referring now particularly to Fig. 1, the magnetic valve 10 has a housing assembly indicated generally as 12 and three tube fittings or nipples 14, 16 and 18, each GB 2 152 756A 2 having a cylindrical flow opening 20, 22 and 24, respectively- The opening 24 communicates with a central chamber 26 within the housing 12 at all times whereas the openings 20 and 22 communicate with the central chamber 26 at selected times to be described more particularly below. The magnetic valve 10 further has an electromagnet inside the housing 12 indicated generally at 28 which comprises a coil 30 and a core 32. The coil 30 has a number of turns or convolutions of a conductor 34 (fewer ampere-turns than those of competitive prior art magnetic valves of like utility) about a stem portion 36 of the core 32The conductor 34 is connected at one end thereof to a first terminal 38 which extends outside of the housing 12, and at the other end to a second terminal 40. also extending outside of the housing 1 2_ The terminals 38 and 40 are mounted in an insulating block 42, which constitutes one part of the housing 12, which is adapted to position the terminals 38 and 40 for conve nient electrical connection.
The magnetic valve 10 further includes a movable valve element or assembly, indicated generally at 44, consisting of a resilient mem ber 46, or rubber or other elastomeric ma terial or the like, and an armature member 48 constructed of a magnetic material, Le_ a material having low reluctance to magnetic flux such as iron, steel, electronic silicon steel, or other suitable ferromagnetic material. The resilient member 46 has a first substantially flat surface portion 50 which is adapted to sealingiy engage a first valve seat 52 at the interior end of the opening 20 when the movable valve assembly 44 is in the extreme leftward position as shown. The resilient member 46 has a second substantially flat surface portion 54 which is adapted to sealingly engage a second valve seat 56 when the movable valve assembly 44 is in the extreme rightward position. As can be seen in Fig. 1, the cylindrical opening 22 extends axially from the fitting 16 through the stem portion 36 to the valve seat 56. The movable valve assembly 44 is resiliently biased to the left by a light, coiled-spring member 58 which preferably engages an annular groove 60 in the armature member 48 at its one end and abuts the surface 62 of the core 32 at its other end so as to be prestressed in compression.
It can now be seen that a fluid path is provided from the opening 20 to the opening 24 by the valve seat 52. Moreover, the flow of fluid by the valve seat 52 may be restrictively influenced or terminated by seating the substantially flat surface portion 50 of the resilient member 46 on the valve seat 52. Accordingly, seating of the flat surface portion 50 on the valve seat 52 restricts or terminates fluid flow through the magnetic valve 10 from opening 24 to opening 20. Similarly, a fluid path is provided from the opening 22, by the 3 valve seat 56, to the opening 24. Moreover, the fluid flow by the valve seat 56 is restric tively influenced or terminated by seating the substantially flat surface portion 54 on the valve seat 56 to restrict or terminate flow through the valve 10 from opening 22 to opening 20.
The housing assembly 12 has an end cap assembly 64 which preferably is integrally molded of nylon or other plastic material. As 75 can be seen in Fig. 1, the end cap assembly 64 includes tube fittings 14 and 18, as well as the first valve seat 52. The valve seat 52 is preferably centrally disposed and is formed by an elevated radiused annular projection 66 as 80 shown. The end cap 64 has three rounded armature support projections 68 (one not shown) which are circumferentially equally spaced and which project a predetermined distance with respect to the valve seat 52 as 85 will be described in greater detail hereinafter.
The end cap 64 additionally includes a rounded inwardly-extending lip portion 74 which engages an outwardly curved left end portion 76 of a cylindrical body 78 so as to secure the end cap 64 to the body 78. A projection 80 on the end cap 64 engages an inwardly extending flange 82 on the curved left end portion 76 of the cylindrical body 78 so as to provide an axial engaging force between the curved lip 74 and the curved end portion 76 of the cylindrical body 78 thereby establishing a fluid seal therebetween. An additional fluid seal between the end cap 64 and the cylindrical body 78 is provided by an 100 0-ring 84 residing in a groove 86 therefor in the end cap 64. The 0-ring 84 forcibly engages the end cap 64 and the curved end portion 76 of the cylindrical body 78 by -1,0 virtue of its distension while in place as shown. The preferred method of assembling the end cap 64 to the cylindrical body 78 includes the steps of inserting the 0-ring 84 in the groove 86 and placing the end cap 64 on the cylindrical body 78. The lip 74 is 110 initially axially extending rather than curved as shown. The lip 74 is curved over the end portion 76 of the cylindrical body 78 by applying heat and radially inward force thereto, for example, by a spinning operation 115 utilizing a formed spinning tool which heats the material through friction.
The cylindrical body 78 is formed of a magnetic material, i.e., material having a low reluctance, so as to serve as a conductor portion of a magnetic circuit to be described hereinafter. The cylindrical body 78 has a rectangular opening 87 in the side wall thereof which accepts the insulating member 42 previously described.
The housing assembly 12 also includes an end mounting bracket, indicated generally as 88, which includes a mounting flange 90 extending at a right angle with respect to an end plate portion 92. The cylindrical body 78 130 GB 2 152 756A 3 is fixedly secured to the end mounting bracket 88 by means of three tabs 94 extending through slots 96 in the end plate portion 92 which are inwardly bent or folded as shown in Figs. 1 and 2. The end plate portion 92 has an annular outwardly extending flange 98 providing a bore 100 which receives and closely cooperates with the step portion 36 of the core 32. The end mounting bracket 88 is also constructed of a magnetic material so as to constitute an additional portion of a magnetic circuit to be described later.
The housing assembly 12 further includes an annular, U-channel sealing member 102 which is constructed of a high reluctance material such as brass or the like. The Uchannel member 102 has a radially outward portion 104 which engages and is preferably brazed or soldered to the inwardly extending flange 82 and the internal bore of the cylindrical body 78, and radially inward portion 106 engaging and preferably brazed or soldered to a cylindrical portion 108 of the core 32. The U-channel member 102 is resiliently pres- tressed in bending, thereby providing an effective fluid seal between the cylindrical body 78 and the core 32 for the chamber 26.
The left end of the core 32 is provided with a radially extending web 110 and an axially extending flange 112 which is positioned in adjacent, spaced relation with respect to the armature 48. The core 32 is also constructed of a magnetic material so as to constitute yet another portion of the magnetic circuit- The armature member 48 is essentially a flat plate which is preferably circular in outer dimension and has a circular inner bore 114. As can be seen in Fig. 1, the armature 48 rests on projections 68 when the resilient member 46 is seated. The resilient member 46 is preferably circular and of H-cross- section as shown so as to provide a central cylindrical portion 116 connecting left and right circular flanges 1 18 and 120, respectively. The flanges 1 18 and 120 are separated a predetermined amount which is greater than the thickness of the armature member 48 so as to permit limited relative axial movement therebetween. Furthermore, the flanges 118 and 120 are of predetermined width or thinness so as to permit limited resilient deformation as illustrated in Fig. 1 with respect to flange 118 when the flat surface portion 50 is seated on the valve seat 52 with the surface 72 of the armature member 48 also being seated on the armature support projections 68. Similarly, flange 120 will resiliently deform when the second flat surface portion 54 is mated to the second valve seat 56 and the armature mem- ber 48 is at rest on the core flange 112. To establish the above conditions, the relative heights of the armature support projections 68 and valve seat projection 66, as well as the width of the flange 118, are determined such that, when the flat surface portion 50 is 4 in initial contact with the valve seat 52, a slight gap remains between the surface 72 of the armature member 48 and the radiused outward portion 70 of the armature support projections 68. Accordingly, continued move ment of the armature member 48 towards the left under the influence of the coiled-spring member 58 causes deformation of the resili ent circular flange 118 as illustrated in Fig. 1.
Similarly, the relative heights of the valve seat 52 and the core flange 112, as well as the width of the flange 120, are determined to establish a like deformation of the flange 120 when the movable valve assembly 44 is seated to the right. Due to this provision, the valve assembly 44 is forcibly seated regard less of manufacturing variations.
From the foregoing description, it now can be seen that a magnetic circuit has been provided in which a low reluctance flux path is established through the radial web 110, the axial flange 112 and the stem 36 of the core 32, the end plate 92, and the cylindrical body 78 to the inwardly extending flange 82. It can be seen further that when the armature mem ber 48 is in its leftward position, as viewed in Fig. 1, the magnetic circuit is complete through an annular axial air gap 122, the armature member 48, and a second annular axial air gap 124. In other words, the electro magnet 28 has poles 82 and 112 in the vicinity of the armature member 48 which partially bridges the air gap between the poles 82 and 112. Magnetic flux is applied to this circuit through the core 32 from the flux source or windings 30 of the electromagnet 28.
The armature member 48 is preferably cov ered, coated or plated with a non-magnetic material 47, as is shown in Figs. 1 and 4.
The non-magnetic material maintains a predet ermined non-magnetic gap, or -artificial air gap-, between the armature member 48 and the poles 82 and 112 when electromagnet 28 is energized and the armature member 48 is drawn into engagement with poles 82 and 112. The non-magnetic gap controls the mag netic flux flow between the electromagnet 28 and the armature member 48 and reduces the magnetic flux flow to a level less than would result if the magnetic material of armature member 48 were allowed to contact poles 82 and 112 directly. By controlling and limiting such flow of magnetic flux, the force needed to move the armature member away from the poles 82 and 112 may be controlled and reduced, thereby allowing the coiled-spring member 58 to be lighter than if the non magnetic gap were not present. Such reduced force and lighter coiled-spring member 58 also allows the magnetic valve 10 to operate at a faster speed, with reduced response time.
The non-magnetic material 47 may be com posed of any number of known non-magnetic substances, including synthetic materials. 130 GB 2 152 756A 4 However, the preferred non-magnetic material 47 is a composite coating of a first layer of copper, or a copper-containing substance, covered with a second layer of electroless nickel, or a nickel-containing substance. The finished copper layer is relatively smooth, relatively inexpensive and easy to apply by plating or other known methods. The nickel layer is relatively hard and is provided to increase the wear-resistance of the composite non-magnetic material 47- In order to maintain a functional non-magnetic gap, the non-magnetic material 47 is only required in the annular region of the face of the armature member 48 that engages the poles 82 and 112 when the electromagnetic 28 is energized. However, in the preferred arrangement, the entire armature member 48 is covered with the non-magnetic material 47 for pur- poses of economy and ease of manufacture- The non-magnetic gap is formed by plating, coating or covering the armature member 48 with a first layer of the preferred copper material. The coated armature member is then tumbled in a tumbling apparatus, such as those known in the art, to polish the first layer. As is shown in Fig. 4, the armature member 48 will have a radius 49 formed thereon.
The thickness of the first layer in one em bodiment is, in practice, approximately three fourths of the total predetermined non-mag netic gap thicknesss, although one skilled in the art will recognize that such proportion may be varied in accordance with other materials used. The armature member 48 is then plated, covered or coated with a second layer of the preferred electroless nickel and again tumbled to polish the second layer, if deemed necessary. Finally, the armature member 48 is preferably heated to further harden the second layer.
The desired thickness of the non-magnetic gap may be different with different embodi- ments of the magnetic valve 10 for different applications. Such thickness is, however, readily determinable from the foregoing description by one skilled in the art. It should also be noted that the uniformity of such thickness is not critical as will become more apparent later in this description.
In operation, if the magnetic valve 10 is to be used in the normallyclosed mode, the fitting 14 is connected to a source of reduced pressure so as to create a pressure differential across the magnetic valve 10. In one of its intended uses, the fitting 14 is connected to the manifold of an automobile engine so that the opening 20 communicates with manifold vacuum. The fitting 18 is connected to a fluid pressure utilization device. For example, the fitting 18 may be connected to an air conditioning system control for an automobile, an ignition advance diaphragm of the distributor, a damper door for a heating and ventilation GB 2 152 756A 5 system, or a vent control for a fuel tank. If the magnetic valve 10 is to be operated in its normally-open mode, the source of fluid at reduced pressure is connected to the fitting 16. In either case, the unused fitting 14 or 16 may be left open so as to vent the utilization device to atmosphere when the valve is closed, or may be capped to prevent such venting. Moreover, the utilization device may be connected to two different sources by 75 connecting each source to one of the fittings 14 and 16. Obviously, a valve according to this invention may be readily constructed which operates only in the normally-open mode or the normally-closed mode simply by 80 providing only a single fitting 14 or 16 for connection to the vacuum or pressure source.
The magnetic valve 10 is operated or acti vated by delivering electrical power to the terminals 38 and 40 to provide a flow of current through the convolutions 34 and con sequent generation of magnetic flux which flows through the circuit described above. As a consequence of the well known effect of the flow of magnetic flux through the air gaps 122 and 124, a force on the armature mem ber 48 will be established tending to move the armature member 48 to the right, i.e., toward the poles 82 and 112. Due to purpo seful or inherent manufacturing variations, for 95 example, in the height of the armature sup port projections 68, the air gaps 122 and 124, and consequently the circumferential distribution of the flux field about the arma ture member 48, will not be uniform. As a result, the force created by the electromagnet 28 will be unevenly applied to the armature member 48 tending to lift one portion thereof prior to lifting of the remaining portions. Ac cordingly, the initial movement of the arma ture member 48 will or may be an angular movement wherein the armature 48 will pivot about one or two of the armature support projections 68. This effect is regenerative, i.e., initial movement of the armature member 110 48 toward the poles 82 and 112 reduces the air gaps 122 and 124 thereby causing an exponential increase in flux which correspon dingly exponentially increases the force tend ing to move that portion of the armature member 48 to the right. As will be appreci ated in view of Fig. 1, initial movement of the armature member 48 is opposed only by the coiled-spring member 58 since the circular flanges 118 and 120 are spaced apart more than the thickness of the armature member 48. After a predetermined limited pivotal movement of the armature, the aforementioned armature portion engages the corre- sponding portion of the radial lip 120 of the resilient member 46. Prior to this engagement of the resilient lip 120, the armature member 48 will obtain an initial angular velocity or impetus which provides an inertia force which is at least partially expended on the resilient member 46 to overcome the seating force caused by the pressure differential across the valve seat. A synergistic effect is achieved since only one radially outwardly portion of the resilient member 46 is being forcibly acted upon such that the initial effect of the armature engagement is to---peel-or---pry--the resilient member 46 from the valve seat 52. The initial pivotal movement of the armature member 48 and the consequent---prying- or -peeling- action can be more easily seen with reference to Fig. 3 in which a partial cross-sectional view of the magnetic valve 10 is shown in a transient state immediately after activation thereof. Note that the armature 48 is in contact with a radially outward portion of the resilient lip 120 after having undergone an initial angular movement and is consequently applying a concen- trated force tending to lift, peel or pry the resilient member 46 from the valve seat 52 at only one portion thereof so as to cause an initial rush of fluid by that valve seat portion. A second regenerative effect is achieved in that the initial rush of fluid rapidly reduces the pressure differential across the valve seat 52, and correspondingly reduces the force necessary to lift the resilient member 46 from the valve seat 52. Accordingly, the momentary high force provided by the inertia of the armature 48 member is applied when a momentary high force is required so as to---crackthe valve and equalize the pressure across the valve. Once the valve is ---cracked-- -a much lower force requirement exists which can be supplied by virtue of the magnetic flux itself.
Consider now the operation of the magnetic valve 10 in the normally-open mode in which the fitting 16 is connected to a source of reduced pressure, for example, to a manifold of an automobile engine. Upon energization of the electromagnet 28, the armature member 48 will be pulled fully to the right, thereby sealingly engaging the second flat surface portion 54 with the second valve seat 56 so as to terminate flow by the second valve seat 56. Upon deenergization of the electromagnet 28, the armature member 48 will move leftward under the influence of the spring 58.
However, the flux decay is not uniform with respect to the armature 48, because the thickness of the non-magnetic material 47 is not perfectly uniform as a result of manufacturing tolerances in the above-described preferred tumbling process. Accordingly the armature 48 pivotally engages the circular flange 118 of the resilient member 46 tending to peel or pry the member 46 from the valve seat 56. During this initial movement, an inertia is acquired by the armature member 48 which aids the lifting of the resilient member 46 from the valve seat 56 against the pressure differential established by the vacuum in the opening 22. Accordingly, the limited axial movement between the armature 48 and the 6 GB 2 152 756A 6 resilient member 46 and the pivotal movement of the armature 48 also aids in unseating the resilient member 46 when the magnetic valve 10 operates in the normally-open mode in a manner similar to that described above i ' n connection with the operation of the magnetic valve 10 in the normallyclosed mode.
In the illustration of Fig. 3, it can be seen that the resilient member 46 comprises very flexible radial flanges 118 and 120 and a relatively much less flexible central portion 116. Consequently, lifting of the resilient valve member 46 is more in the nature of a ---prying-effect rather than a -peeling- effect. More of a---peeling- effect can be obtained by using relatively rigid flanges (or other mounting means for member 46) and a relatively flexible central portion. If desired, any combination of flexibilities may be used to mix these effects so long as the resilient member 46 remains in operative association with the armature member 48. The combined effects of the inertia force provided by the intial movement of the armature member 48 and the pivotal movement applying a substantial force to only one radial outward portion of the resilient member 46 allows satisfactory operation of the magnetic valve 10 with a lesser flux requirement than magnetic valves currently in use. Consequently, the number of ampere-turns in the magnetic source 30 may be reduced at a significant reduction in the cost of a suitable magnetic valve. Moreover, the flat valve configuration, as opposed to a needle valve configuration, required only small excursion of the movable valve assembly 44 with respect to the valve seat 52 to achieve minimum flow restriction by the valve seat.
An alternate embodiment of the magnetic valve 10 may be constructed by providing at least the poles 82 and 112 of the electromagnet 28 with the non-magnetic material 47 as is described above for the covering of the armature member 48. Thus the non-magnetic gap may alternatively be provided on the electromagnet 28 rather than on the armature member 48.
Alternatively, an exemplary valve may also 115 be constructed by utilizing a movable core.
The movable core is connected to the plate carrying the resilient member 46 such that movement of the core in response to energiza- tion of the flux source will lift the resilient member 46 from the valve seat 52. Preferably, the connection between the movable core and the plate or the association between the plate and the resilient member 46 is askew or pivotal so as to give the---prying-action described above. For example, the member 48 may have an angulated flange to achieve the askewed association. Of course, it is preferred to provide limited relative movement between the plate and movable core or the plate and resilient member 46 to establish an initial impetus or inertia prior to lifting the resilient member 46 from the seat 52. In such an embodiment, the non-magnetic material should be located at least in the portion of the core that is in close proximity with the windings 30- In one constructed form the three projections 68 were replaced by an annular member ridge formed integrally with the end cap 64 and being continuous except only for an interruption or opening adjacent the opening 24 to provide a passageway for air flow between opening 24 and the air volume centrally in- side of the annular member. In that constructed form, the surface of the annular member facing the armature member 48 was flat and about 0.025 inches wide and the diameter was somewhat larger than that of the circular focus of the projections 68, the outer diameter being about the same as the diameter of armature member 44 so as to preclude any significant movement of any part of the armature 44 in the direction of the end cap 64 (towards the left in Fig- 1) during tilting, an arrangement now preferred. As with projections 68, the annular member preferably projects slightly further (e.g., 0-011 inches) from the inner face of the end cap 64 than the valve seat 52 does.
In view of the above description of exemplary versions of magnetic valve 10, it will now be appreciated that a magnetic valve is provided which can operate faster, with more rapid response times, and with lower flux levels, and consequently, fewer ampere-turns than with prior art devices. As a result, a substantial cost savings is achieved. Moreover, it can be seen that the alignment be- tween the resilient member 46 and the valve seats 52 and 56 is not critical, and accordingly, the parts may be manufactured, and the non- magnetic gap may be formed, with convenient tolerances, and thus assembly and manufacture may be economically and easily accomplished. Furthermore, any dimensional variations due to wear also are not critical thereby contributing to the reliability and longevity of the device.
CLAIMS 1. A method of forming a non-magnetic gap between a magnetic fluxproducing apparatus and a magnetic armature engageable with said magneticflux-producing apparatus, comprising the steps of: covering said armature member with a first layer of a nonmagnetic material; polishing said armature to smooth the surface of said first layer; covering said first layer with a second layer of a relatively hard non-magnetic material; and polishing said armature to smooth the surface of said second layer; said first and second layers thereby forming said non-magnetic gap.